Fuel injection pump of the distribution type

Abstract

A distribution type fuel injection pump includes a control cylindrical bore into which a control plunger is fitted. The control plunger partitions the control cylindrical bore into first and second chambers. The same pressure as that of fuel in the pumping chamber (which serves to feed fuel) is transmitted to the first chamber, while fuel is supplied to the second chamber through a control passage. An electromagnetic valve is arranged in the control passage and the amount of fuel with which the second chamber is filled is adjusted by controlling the electromagnetic valve.

What is claimed is: 
     
       1. A distribution type fuel injection pump for delivering fuel to each of the combustion chambers in an internal combustion engine comprising: pump housing means including a pumping head in which a pumping chamber is defined;   first fuel supply means for supplying fuel to the pumping chamber;   fuel pressurizing means for applying pressure to the fuel in the pumping chamber;   distributor means for distributing and delivering the fuel, which has been pressurized in the pumping chamber, to each of the combustion chambers in the engine;   control plunger means actuated by the fuel pressure in the pumping chamber and including a control cylinder bore defined in the pumping head and a control plunger fitted into the control cylinder bore, the control cylinder bore being partitioned into a first chamber to which the fuel pressure in the pumping chamber is transmitted and which serves to apply this pressure to one end of the control plunger, and a second chamber defined by the other end of the control plunger;   second fuel supply means for supplying an adjusted amount of fuel to the second chamber and including a control passage connected to the second chamber and an electromagnetic valve for opening and closing the control passage; and   escaping means for allowing the fuel to escape from the second chamber when the fuel pressure in the second chamber becomes higher than a certain value.   
     
     
       2. A distribution type fuel injection pump according to claim 1, wherein the first fuel supply means includes a feed pump driven by the engine and a fuel suction passage for connecting the feed pump to the pumping chamber. 
     
     
       3. A distribution type fuel injection pump according to claim 2, wherein the first fuel supply means further includes a second electromagnetic valve for opening and closng the fuel suction passage. 
     
     
       4. A distribution type fuel injection pump according to claim 1, wherein the fuel pressurizing means includes a cylinder bore connected to the pumping chamber, a free piston fitted into the cylinder bore, defining the pumping chamber by one end thereof while defining a pressure receiving chamber by the other end thereof, a booster chamber linked with the pressure receiving chamber and defined between a pair of pump plungers, a third fuel supply means for supplying fuel to the booster and pressure receiving chambers, and a cam means for reciprocating the paired pump plungers, synchronous with the engine rotation, to thereby pressurize the fuel in the booster chamber. 
     
     
       5. A distribution type injection pump according to claim 4, wherein the first chamber is linked with the pressure receiving chamber. 
     
     
       6. A distribution type fuel injection pump according to claim 1, wherein the first chamber is open to the pumping chamber. 
     
     
       7. A distribution type fuel injection pump for delivering fuel to each of the combustion chambers in an internal combustion engine comprising: pump housing means including a pumping head in which a pumping chamber is defined;   first fuel supply means for supplying fuel to the pumping chamber;   pumping plunger means for pressurizing the fuel in the pumping chamber and including at least a pumping plunger and cam means for reciprocating the pumping plunger in response to the engine rotation;   distributor means for distributing and delivering the fuel, which has been pressurized in the pumping chamber, to each of the combustion chambers in the engine;   control plunger means actuated by the fuel pressure in the pumping chamber and including a control cylinder bore defined in the pumping head and a control plunger fitted into the control cylinder bore, the control cylinder bore partitioned by the control plunger into a first chamber to which the fuel pressure in the pumping chamber is transmitted and which serves to apply this pressure to one end of the control plunger, and a second chamber defined by the other end of the control plunger;   second fuel supply means for supplying an adjusted amount of fuel to the second chamber and including a control passage connected to the second chamber, and an electromagnetic valve for opening and closing the control passage; and   escaping means for allowing the fuel to escape from the second chamber when the fuel pressure in the second chamber becomes higher than a certain value.   
     
     
       8. A distribution type fuel injection pump according to claim 7, wherein the first fuel supply means includes a feed pump driven by the engine and a fuel suction passage for connecting this feed pump to the pumping chamber. 
     
     
       9. A distribution type fuel injection pump according to claim 8, wherein the first fuel supply means further includes a second electromagnetic valve for opening and closing the fuel suction passage. 
     
     
       10. A distribution type fuel injection pump according to claim 7, wherein the pumping plunger means includes a cylinder bore connected to the pumping chamber, a free piston fitted into the cylinder bore, defining the pumping chamber by one end thereof while defining a pressure receiving chamber by the other end thereof, a booster chamber linked with the pressure receiving chamber and defined between a pair of pump plungers, and third fuel supply means for supplying fuel to the booster and pressure receiving chambers. 
     
     
       11. A distribution type fuel injection pump according to claim 10, wherein a cam means includes a cam ring which covers the paired pump plungers, inner face of which is formed as a cam face, and cam rollers attached to the other ends of the pump plungers through roller shoes and contacted with and slid on the cam face. 
     
     
       12. A distribution type fuel injection pump according to claim 10, wherein the first chamber is linked with the pressure receiving chamber. 
     
     
       13. A distribution type fuel injection pump according to claim 11, wherein an adjuster means includes a timing controller in which a cylinder bore is defined, a timing piston fitted into the cylinder bore, partitioning the cylinder bore into a timing chamber and a spring housing chamber, means for supplying fuel to the timing chamber, the fuel having a pressure in accordance with the number of engine rotations, a spring housed in the spring housing chamber to urge the timing plunger toward the timing chamber, means for connecting the timing piston to a cam ring to match its movement to the rotation of the cam ring, and means for allowing the fuel in the timing chamber to escape at a predetermined timing, and including an electromagnetic valve. 
     
     
       14. A distribution type fuel injection pump according to claim 7, wherein the pumping plunger is rotated synchronously with the engine and said cam means includes a face cam attached to that one end of the pumping plunger which is remote from the pumping chamber, and a roller ring having plural rollers arranged opposite to the cam face and contacted with and slid on the cam face of the face cam. 
     
     
       15. A distribution type fuel injection pump according to claim 14, wherein the adjuster means includes a timing controller in which a cylinder bore is defined, a timing piston fitted into the cylinder bore, partitioning the cylinder bore into a timing chamber and spring housing chamber, means for supplying fuel to the timing chamber, the fuel having a pressure in accordance with the number of engine rotations, a spring housed in the spring chamber to urge the timing plunger toward the timing chamber, means for connecting the timing piston to a cam ring to convert the movement of this timing piston to the rotation of the roller ring, and means for allowing the fuel in the timing chamber to escape at a predetermined timing and includng an electromagnetic valve. 
     
     
       16. A distribution type injection pump according to claim 15, wherein the first chamber is communicated directly with the pumping chamber.